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Current Feature Articles   Nov 20 The Amateur Radio Crossword Puzzler   Nov 20 Adventure in the Arctic: VO2A Expedition to Labrador   Nov 20 Surfin': More Radio Piracy on the High Seas   Nov 16 Youth@HamRadio.Fun: Fall Magic   Nov 13 Surfin': The Real Pirate Radio   Nov 06 Surfin': Homebrewing Today   Nov 05 DX the Hard Way   Nov 02 ARRL In Action: What Have We Been Up to Lately?   Nov 01 It Seems to Us: It Doesn't Just Happen   Oct 30 Surfin': Mapping Up ARRL Products: CD-ROMs (More) The ARRL Emergency Communication Library v. 1.0 -- CD-ROM. Informative documents and presentations on many aspects of emergency communication operating. The ARRL Antenna Book -- The ultimate reference for Amateur Radio antennas, transmission lines and propagation. Fully-searchable CD-ROM included. 21st edition. NCJ Collection CD-ROM 1973-1998 -- Back issues of NCJ, the National Contest Journal, on a convenient, space-saving CD-ROM. The ARRL Digital Technology for Emergency Communications Course -- Now Shipping! -- CD-ROM. Learn all the ways to use digital technology as an emergency communications tool! The ARRL Software Library for Hams 3.0 -- Now Shipping! -- CD-ROM, Version 3.0. Quick access to utilities, applications and information.

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Talking all about airplanes last week led to airplane bounce software this week.

G3PPT's VHF Communication via Aircraft Reflections Web page describes the aircraft propagation anomaly and includes software to experiment with this RF incongruity.

After reading last week's Surfin', About Airplanes, Mark Herson, N2MH, wrote to tell me about software that attempts to use the reflections from aircraft in order to make long distance contacts. Lionel Sear, G3PPT, wrote the software, which is called SlowFeldXPAS; you can read all about it at the VHF Communication via Aircraft Reflections Web page.

The Web page describes this propagation anomaly and includes a link to a revealing paper written by Ray Scrivens, G3LNM, explaining the mechanics of aircraft reflections. Lionel then explains how he determined the best mode of operation to use in his software.

According to Lionel, Hellschreiber is not sufficiently sensitive for our purpose, but he developed a very slow form of the mode for use where QRSS CW is used. The software that produced this mode was called SlowFeld, and at some three characters per minute, was very slow, but the sensitivity (readable at a level approaching âˆ'30dB below AWGN) was adequate for this application.

After further experimentation, it took only slight modifications of SlowFeld to produce SlowFeldXPAS, a version dedicated to aircraft scatter use, which you can download from this Web page.

Until next time, keep on surfin'.

Editor's note: Flying by the seat of his pants, Stan Horzepa, WA1LOU, writes Surfin' at least once a week. To contact Stan about airplanes, flight simulators or anything else of interest, send e-mail or add comments to his blog.

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